I ordered the much discussed red LED Ultrafire WF-501B Philips Luxeon K2 flashlight on June 20 from DealExtreme. On July 9 ordered the Cree XLamp XP-C-R2 5-mode 90 lumen red LED drop-in module (thanks to BertieB for posting it was available). The Cree drop in works and now I have a rapidly flashing tail light (about 8 to 10 Hz, similar to the strobe flash rate of a Fenix L2D).
Forewarned of DX's erratic quality control, I was disappointed but not surprised when I first turned the stock WF-501B on to find it had 1 mode, "ON" and "ON". One of the ON modes was a bit erratic so I suspected a short and per a thread on Candlepower forums I knew metal chips or swarf from machining were not always cleaned out (also sometimes bad soldering). I completely unscrewed the light into its five major sub-assemblies and spotted a small sliver of metal inside the tailcap (part with the switch) that looked to bridge across the contacts. After carefully removing it with some fine needle-nose pliers, the light had both an ON and OFF mode. Impressively bright, as others have posted.
I prefer at least some of my rear lights to flash, ideally the distinctive PB Superflash's or some of the Dinotte taillight's modes. When BertieB posted about the Cree drop-in with a flashing mode, I boldly ordered it.
It arrived today and appears to be an almost identical reflector and brass threaded module end to the WF-501B's stock module with a different LED and circuit board (more on those later). Unscrewed the stock module, screwed in the Cree module, and it worked. Beam shape very similar to stock, about as bright (maybe a tad brighter).
There are some differences in the mounting of the LED to the PC board. The stock module I got has some hard white glue beneath and extending out from under the LED (see photo) Anyone know if this might be thermally conductive epoxy?
In contrast, the Cree drop-in does not have anything extending out from underneath but is very close to the PC board. (see photo). I'm uncertain if it actually touches the board but I could not slip any of some 0.003" plastic film underneath the LED. Any comments on this heat-sinking vs. the stock?
The Cree reflector also has a white plastic ring on the back where it could contact the leads from the LED (see photo).
Finally the beam shots.
Coming attraction: Outdoor beam shots at distance with comparison to the Dinotte 140R-AA-R Taillight.